Tablet press systems/tablet tooling also referred as compressing machines in the pharmaceuticals industry are mechanical devices that compress powder into tablets of uniform size and weight. A tablet press can be used to manufacture tablets of a wide variety of sizes and materials, including pharmaceuticals, drugs, cleaning products, and cosmetics.
To form a tablet, the formulation material must be metered into a cavity formed by two punches and a die, and then the punches must be pressed together with great force to fuse the material together. The upper and lower punches along with the die are referred to as a tooling assembly. In the first step of a typical operation, the bottom punch is lowered in the die creating a cavity into which the granulated feedstock is fed. The exact depth of the lower punch can be precisely controlled to meter the amount of powder that fills the cavity. The excess is scraped from the top of the die, and the lower punch is drawn down and temporarily covered to prevent spillage. Then, the upper punch is brought down into contact with the powder as the cover is removed. The force of compression is delivered by high pressure compression rolls which fuse the granulated material together into a hard tablet. After compression, the lower punch is raised to eject the tablet. Therefore, it is of critical importance that said punches and die have accurate dimensions, as faulty punches and die can result in unsatisfactory products which are not within the preset standards.
Many systems exist in the art that facilitates inspection of tools used in pharmaceuticals industry, such as punches and dies of the tablet tooling. In such systems, analysis is performed for identifying defects and/or suspected defects in the measurement of a tooling assembly. Generally, these higher order analyses occur after initial analysis/operations that serve to identify defects/suspected defects, and can comprise more sophisticated analysis that can provide better inspection results.
One such system has been disclosed in U.S. Pat. No. 5,768,138 A. The specification discloses a method for inspecting a tool used in a tableting punch and an apparatus for performing the method. The tool is clamped into a holder which positions it under an imaging device which captures an image of a top of the tool. Based on the captured image, an angular position of the tool is rotated so the tool has a predetermined angle. After the tool is rotated, an image of a profile of a tip of the tool is captured so that the radius of the tip of the tool can be determined.
The level of accuracy in the disclosed system is comparatively less, as it based on vision measurement and evaluates parameters such as working length of a punch on basis of relative measurements for e.g. by measuring cup depth of the punch based on radius of concavity of said punch and subtracting it from overall length to calculate the working length of said punch.
Punches and dies can be of different types. The inspection systems of the prior art require changes in the configuration every time when a different type of tablet tooling system is to be inspected. This leads to manual intervention as generally gauges or masters are required to setting up the fixture. One such system in the prior art is Tooling Inspection and Analysis System by Bosch (hereinafter referred as Bosch system) that is capable of inspecting different types of punches and dies but with the requirement of setting tools whenever a different type of punch or die is to be inspected, thereby increasing the time of inspection and leading to a much higher degree of manual intervention.
Further, the Bosch system has different fixtures to measure different parameters of the tool to be inspected resulting in a further increase of time and manual intervention.
Thus to solve above and other problems there is a requirement of a system that provides an automated inspection of various tablet tooling based on multiple parameters with reduced inspection time and enhanced accuracy.